gh-127385: Add F_DUPFD_QUERY to fcntl (GH-127386)

Author: rruuaanng

Doc/library/fcntl.rst

@@ -79,6 +79,10 @@ descriptor.
    On macOS and NetBSD, the :mod:`!fcntl` module exposes the ``F_GETNOSIGPIPE``
    and ``F_SETNOSIGPIPE`` constant.
 
+.. versionchanged:: next
+   On Linux >= 6.1, the :mod:`!fcntl` module exposes the ``F_DUPFD_QUERY``
+   to query a file descriptor pointing to the same file.
+
 The module defines the following functions:
 
 

Misc/NEWS.d/next/Library/2024-11-29-13-06-52.gh-issue-127385.PErcyB.rst

@@ -0,0 +1 @@
+Add the ``F_DUPFD_QUERY`` constant to the :mod:`fcntl` module.

Modules/fcntlmodule.c

@@ -559,6 +559,9 @@ all_ins(PyObject* m)
 #ifdef F_NOTIFY
     if (PyModule_AddIntMacro(m, F_NOTIFY)) return -1;
 #endif
+#ifdef F_DUPFD_QUERY
+    if (PyModule_AddIntMacro(m, F_DUPFD_QUERY)) return -1;
+#endif
 /* Old BSD flock(). */
 #ifdef F_EXLCK
     if (PyModule_AddIntMacro(m, F_EXLCK)) return -1;